Self-cleaning spark plug



F eb. 3, l 925.

G. SEIBERT, JR

SELF CLEANING SPARK PLUG Filed July 21, 1922 f 6 0 lmwv 3 a ma ma@ w L a Zfo F M/ ii; M

Patented Feb. 3, 1925.

UNITED STATES 'GEORGE SEIBERT, JR., 0F ALBIA., IOWA.

SELF- CLEANING SPARK PLUG.

Application mea July 21, 1922. serial No. 576,448.

this character which will be simple in construction, comparatively 'inexpensive to manufacture and lmore efficient in operation than those which have been `heretofore proposed. i A further object of the invention-is to l provide a spark plug which will quickly and eliiciently remove any carbon or other deposits which may accumulate adjacent the spark gap, thereby preventing the short circuiting of the plug and the mis-firing of the cylinder.

A Sau further object .of the invention is to provide a spark plug in which the cleaning 'feature may be either automatically or manually actuated, or which, if desired, may be rendered inoperative at will, under which conditions the plug may be used in the same manner as the ordinary spark plug.v

With the above and other yobjects in view which will appear as the description proceeds, the invention consists in the novel details of construction and combinations ofv 4parts more fully hereinafter disclosed and particularly pointed out in the appended claims.

In the accomp'anyinoF drawingsforming a part ot this specification in which like numerals designate like parts in all the views: Figure 1 is a central, vertical, sectional view partly in elevation of one form of spark plug, made in accordance with the present invention;

iig. 2 is a horizontal sectional view taken .f approximately on the plane indicated by the line 2-2 of Fig. 1;

Fig. 3 is a fragmentary, central, vertical, sectional View of a slightly modified form of the invention;

F ig. 4 lis a diagrammatic elevational view illustrating the manner of manually controlling the cleaning feature; and,

Fig. 5 is a horizontal sectional view taken approximatel onthe plane indicated by the line 55 of igfv. 4.

Referring more especially to Figs. 1 and 2, the numeral 10 indicates the metallic shell or casing of the plug, the lower end of which is preferably threaded as at 11, to engage the usual threads in t-he cylinder walls ofv the engine. The upper end of the said shell 10 is preferably enlarged, as at 12, and is recessed and threaded, as at 13, to receive the lower portion 14 of a porcelain or other suitable insulating member 15, which is normally retained in place by means of the threaded bushing 16, engaging the shoulder or flange 17, with which the said lower portion 14 is provided.

The said shell is provided with a central bore 18 extending entirely through the same, the upper portion of the said bore being enlarged-as at 19, and the two portions being connected by an inclined surface 20, serving as a valve seat, as will presently appear. a.

The insulating member 15 is provided with an axial bore 21 in which is slidably mounted the central electrode 22 which extends entirely through the said member 15 and axially of the bores 18 and 19 to a point below the lower end of the shell or casing 1Q. The said lower end of thecasing is provided with the usual curved electrode 23 which is suit-ably spaced from the` electrode 22 to provide a spark gap 24, as is well known.

The said electrode 22 has rigidly secured to it a piston 25 ofsuitable insulating material, which is surrounded by a sleeveof metal 26. rllhe said piston is of such a diameter as to freely slide within the bore 18 and its upper end is lared as at 27 to provide a valve surface adapted to coact with the inclined valve seat 20, abovev described.

A coiled compression spring 28 is interposed between the upper surface of the said piston 25 and the ange 17 of the insulating member 15 within the enlarged bore 19, and tends to normally :torce the said piston downwardly, as will be readily apparent.

The lower portion 14 of the insulating member 15 is extended downwardly to provide a depending hollow sleeve 30 which is interposed between the coils of the spring 28 and the central electrode 2 2, and at the junction of the said sleeve 30 with the lower end 14 of the insulating member 15, there is provided a valve seat 31, adapted to be engaged by a valve member 32, rigid with the said electrode 22.

The upper end of the said electrode 22 extends out of the insulating member Jfor some distance, and is provided with the usual the said pistondownwardly until its flared valve 27 seats upon the inclined surface 20 of theshell 10. This downward movement of the piston carries with it the central electrodeY 22, as well as the small valve 32, thereby unseating the latter. i

As the piston moves downwardly, its sides and lower end serves to clean out any carbon which may have been deposited upon the walls of the bore 18, thereby preventing the said carbon from building up within the said bore to such a point that the current will jump from the cent-ral electrode to the carbon deposit rather than across the spark gap 24.

Upon the upward stroke of the engine piston, during which the gas within the cylinde-r is compressed, the pressure will force the piston 25 upwardly against the compression of. its spring 28, thereby causing 1t to reassume the position illustrated in Figure 1. The upward movement of the said pisl ton carries with it the central electrode 22,

together with` the valve member 32 and causes the latter to engage the valve seat 31, thereby preventing the escape of any of the compressed gas around the cylinder 4of the central electrode. k

In the form of the invention illustrated in Fig 3, the central electrode 22, instead 0f sliding within the porcelain insulating member 15, isrigidly held, while the piston 25' is slidably mounted thereon. In this\for1n as well as in the form illustrated in Fig. 1, the said piston is preferably provided with a reduced downward extension 36, which is adapted, when the said piston is in its lowermost position, to surround the lowermost end of the elect-rode 22 and extend into the spark gap between the electrodes 22 and 23, as is clearly illustrated in Fig. 3. It willl thus 'be seen that both forms not only clean the walls 'of the bore 18, but also the actual sparking points of the electrodes, 22- and .23. In some instances where the plugs are used in motors which do not deposit much carbon it is possible to manually control the movements of the piston 25 instead of depending upon t-he suction and Ycompression within the engine cylinders.'

vIn Figure 4, I have illustrated onemeans whereby such manual control may be accomplished. The said means comprises a bracket 40 which ma be adjustably secured to the body of the p ug by means of a lock nut 41 engaging the threads of the bushing 16. The said bracket 40 has pivoted to its upper end, as at 41, a bell crank lever 42, one arm of which 43 is bifurcated as at 44 to straddle the central electrode 22 and engage the insulating washer 45 with which the said electrode is provided. The other arm 46 of the bell crank lever 42 is .pivotallyconnected, asat 47, to an operating rod 48, which extends to and through the dash 49 of the vehicle and is rovided with la suitable handle, 50 where y it may be In Figure 4 the parts are shown in their operative positions with the electrode 22 the piston 25, carried thereby, in their lower or cleaning positions, they having been movedto these positions by sliding the operating rod 48 toward the left, as seen in the said Fig. 4. This movement of the said rod 48 through the bell crank lever connections .has forced the electrode 22, together with its piston l25, downwardly, thereby cleaning out the'l carbon from the bore 18, as was above disclosed. The parts, of course, are restored to their normal positions illustrated in Fig. 1 by moving the rod 48 toward the right, as seen in Fig. 1, which lifts the electrode 22 and the piston 25, as willbe readily apparent.

Should it be desired to render the cleaning piston25 inoperative when using the plug with engines which do not pump oil or deposit large amounts of carbon, it is only necessary to adjust the nuts 33 and 34 upon the electrode 22 until the nut 33 engages the upper surface 51 ofthe porcelain insulating member 15, thereby drawing the electrode 22 to its uppermost position with its valve 32 engaging the seat 31. When so adjusted it will be apparent that the piston 25 andthe electrode 22 cannot descend upon the suction stroke of the engine and the plug may be fused in the same manner as the usual stationary electrode plug.

, It will beseen that all the forms of this invention provide means whereby fouled spark plugs may be readily and eii'ective'ly cleaned of the carbon or other deposits there- -by eliminating the necessity of removing the plugs from the engine for accomplishing the cleaning.

It is obvious that those skilled in the art may vary the details of construction, as Well as the arrangement of parts without depart- -ing from the spirit of the invention, therefore it is not wished to be limited tothe above disclosure except as may be required by the claims.

What is claimed is: f 1. A spark plug for internal combustion engines comprising a shell, one end of which is provided with an electrode; an insulating core member carried by said shell; a central electrode carried by said core member, forming a spark gap with said first mentioned electrodeya piston slidably mounted within said shell surrounding said electrode, adapted to remove deposits of foreign matter from the inner-Walls of said shell, said piston being provided with a reduced extension adapted to slidingly engage said shell carried electrode to clean the same; and a. spring Within said shell normally urging said piston tovsaid cleaning position.

2. A spark plug for internal combustion engines comprising a shell, one end of which is'provided with an electrode; an insulating core member carried by said shell; an integral central electrode slidably mounted in said core member, 'projecting beyond the ends of said shell and forming a spark gap with said first mentioned electrode; a piston provided with a reduced extension, carried by said central electrode, adapted to clean the inner Walls of said shell and said shell carried electrode, said piston being y movable in one direction by the pressure of in the opposite direction; and a valve member carried by said central electrode for preventing the escape ofthe compressed gases from said cylinder.

3. A spark plug for internal combustion engines comprising a shell, one end of which is provided with an electrode; an insulating core member provided with a valve seat, carried by said shell; an integral central electrode slida-bly mounted in said core member with its ends projecting beyond the ends of said shell, one of them being threaded, and the other forminga spark gap with said first mentioned electrode; a piston provided with a. reduced extension, carried by said central electrode, adapted to clean deposits of foreign matter from the inner Walls of said shell, and from said shell carried electrode, said piston being movable in one direction by the pressure of the gases within the engine cylinder; a spring interposed between said core member and said piston, for

moving the latter in the opposite direction; a valve member carried by said central electrode for engagement with said valve seat for preventing the escape-of the compressed gases from said engine cylinder; and a nut carried by the threaded end of said central electrode, adapted` to prevent movement thereof. ,Y

In testimony whereof I affix my signature.

, `GERGE SEIBERT, Jn. 

